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In the expression 6/x vision, the numerator (6) is the distance in metres between the subject and the chart and the denominator (x) the distance at which a person with 6/6 acuity would discern the same optotype. Thus, 6/12 means that a person with 6/6 vision would discern the same optotype from 12 metres away (i.e. at twice the distance).
Near visual acuity or near vision is a measure of how clearly a person can see nearby small objects or letters.Visual acuity in general usually refers clarity of distance vision, and is measured using eye charts like Snellen chart, LogMAR chart etc. Near vision is usually measured and recorded using a printed hand-held card containing different sized paragraphs, words, letters or symbols.
Outside the United States, the standard chart distance is 6 metres (20 ft), and normal acuity is designated "6/6". Other acuities are expressed as ratios with a numerator of 6. Some clinics do not have 6-metre eye lanes available, and either a half-size chart subtending the same angles at 3 metres (9.8 ft), or a reversed chart projected and ...
Foggy morning road On clear days, Tel Aviv's skyline is visible from the Carmel mountains, 80 km north. In extremely clean air in Arctic or mountainous areas, the visibility can be up to 240 km (150 miles) where there are large markers such as mountains or high ridges. However, visibility is often reduced somewhat by air pollution and high ...
Height of the Salto Angel, the world's highest free-falling waterfall 10 3: 1 kilometer 2.3 km Length of the Three Gorges Dam, the largest dam in the world [34] [35] 3.1 km Narrowest width of the Strait of Messina, separating Italy and Sicily: 8.848 km Height of Mount Everest, the highest mountain on Earth 10 4: 10 km: 10.9 km
A pilot's view of Lisbon Airport's runway 21 in fog; runway visual range is about 200 m (660 ft). In aviation, the runway visual range (RVR) is the distance over which a pilot of an aircraft on the centreline of the runway can see the runway surface markings delineating the runway or the lights delineating the runway or identifying its centre line.
The U.S. Food and Drug Administration (FDA) now classifies eggs as a “healthy, nutrient-dense" food, according to a new proposed rule. Registered dietitians react to the change.
A typical example of long-distance observation. The Tatra Mountains as seen from the Łysa Góra, in southeast Poland, at a distance of about 200 km (120 mi).. Long-distance observation is any visual observation, for sightseeing or photography, that targets all the objects, visible from the extremal distance with the possibility to see them closely.